Similar bursts of energy are visible while looking at the gravitational radiation power emitted by a binary black hole-white dwarf system, Fig. REF . However, the amount of energy radiated via gravitational waves remains a few orders of magnitudes lower than the energy emitted electromagnetically, compare Figs. REF  and REF  for the case of \(M_{\rm BH}/m_{\rm wd} = 10\) . For such a stellar-mass black hole-white dwarf systems a peak gravitational-wave luminosity at a periastron passage is of the order of \(10^{33}\,\) erg s\(^{-1}\)  (Fig.REF ). For an intermediate-mass black holes (\(M_{\rm BH}/m_{\rm wd} = 10^3\) ) case a peak of radiation power increases up to \(10^{39}\,\) erg s\(^{-1}\) . This is, not surprisingly, much less than the maximum gravitational-wave luminosity detected in GW150914 event, the first observation of gravitational waves from the merger of two stellar-mass black holes [1]}, which was \(10^{56}\,\) erg s\(^{-1}\) . Two years later LIGO and Virgo detectors made the first observation of a binary neutron star inspiral, known as the signal GW170817 [2]}. The energy radiated via gravitational waves in this event was estimated from below as \(0.025 M_{\odot } c^2\) . Combined with the knowledge of a duration of a gravitational wave signal, which lasted for approximately 100 seconds, leads to average radiation power at least of the order of \(10^{52}\,\) erg s\(^{-1}\) . Merger of binary neutron stars was followed by a short \(\gamma \) -ray burst GRB 170817A [3]} located in the same sky position, thus linking a short bursts of \(\gamma \)  rays to coalescence of neutron stars. The power radiated electromagnetically by GRB 170817A event was estimated as of the order of \(10^{46}\,\) erg s\(^{-1}\) , much less than the power radiated via gravitational waves.
<FIGURE>